The approaches described in this section are approaches that could be pursued, but not necessarily approaches that have been previously conceived or pursued. Therefore, unless otherwise indicated, it should not be assumed that any of the approaches described in this section qualify as prior art merely by virtue of their inclusion in this section.
Database consolidation involves distributing and sharing computer resources of a hardware platform among multiple databases. Important objectives of database consolidation include isolation, transportability, and fast provisioning. Isolation is the ability to limit an application's access to the appropriate database. Transportability is the ability to efficiently move databases between hosts. Fast provisioning is the ability to quickly deploy a database on a host.
In non-consolidated databases, database backup and recovery may be performed on a per-database basis. However, in a consolidated database or other in-database virtualizations capable of consolidating multiple databases, traditional database backup and recovery practices cannot be carried out on a per-database basis with the same behavior expected of a non-consolidated database.
For example, when a database is restored to a restore point from a database backup, the database backup is recovered, and redo records are processed from the time of the database backup to the restore point. Recovery time is roughly proportional to the time elapsed between the database backup and the restore point. In a non-consolidated database, the restore point typically corresponds to the point the non-consolidated database was closed or otherwise made inactive. The redo log of the non-consolidated database does not grow when the non-consolidated database is inactive. In a consolidated database environment that implements a shared redo log, the recovery time for a particular database may be unbounded since the redo log grows even when the specific pluggable database is inactive.
Discussed herein are approaches for database backup and recovery on a per-database basis in a consolidated database system.